Many print head architectures use a stack of plates referred to as a jet stack to route ink from the ink reservoirs to a print substrate, where the plates may consist of thin plates of stainless steel, polymer sheets, etc. The ink flows through chambers and channels formed when the plates are stacked together, exiting the stack through a nozzle, or jet, plate that typically consists of an array of small holes. Electrical signals control a transducer of some sort that acts against a side of the jet stack to pull ink into a chamber adjacent each nozzle and then push it out the nozzle.
Typically, the electrical signals reach the transducers through a flex circuit adhered the jet stack. The flex circuit adheres to the jet stack with an adhesive layer formed of one or more polymer layers. The adhesive layer or layers have an array of holes to allow a conductive paste or other conductive material to contact the transducers and make electrical connections with the flex circuit.
As the need for higher resolution printer increases, the density of the nozzle apertures on the plate increases. This in turn increases the density of the holes in the adhesive standoff layer. The holes generally become smaller with the increased density. When the conductive paste applied to these holes, the air has no outlet, unlike the larger holes that accommodated more air flow. The air becomes trapped and can interfere with the electrical connection between the transducer and the flex circuit causing this connection to fail. This results in signals not reaching the transducer, so ink does not get expelled from the corresponding nozzle correctly, causing imaging artifacts in the printed image.